Editing Proportional representation (section)

==== Single transferable vote ====
{{Main|Single transferable vote}}

The single transferable vote (STV), also called [[Ranked voting|ranked choice voting]], is a [[ranked voting|ranked system]]: voters rank candidates in order of preference. Voting districts usually elect three to seven representatives; each voter casts just one vote. The count is cyclic, electing or eliminating candidates and transferring votes until all seats are filled. A candidate whose tally reaches a [[Droop quota|quota]], the minimum vote that guarantees election, is declared elected. The candidate's surplus votes (those in excess of the quota) are transferred to other candidates at a fraction of their value proportionate to the surplus, according to the voters' preferences. If there are no surplus votes to transfer and there are still seats to fill, the least popular candidate is eliminated, those votes being transferred to their next preference at full value. The votes are transferred according to the next marked preference. Any votes that cannot be transferred are moved to a pile labelled exhausted or non-transferable.{{Citation needed|date=May 2025}}

The count continues until all the seats are filled or until there is only one more candidate than the number of remaining open seats. At that point all of them except the least popular candidate are declared elected, even if they do not have quota.

The transfer of votes of eliminated candidates is simple{{snd}}the transfer of surplus votes is more involved. There are various methods for transferring surplus votes.

Manual methods used in early times and still today in places where STV was adopted in early 20th century (Ireland and Malta) transfer surplus votes according to a randomly selected sample, or transfer only a segment of the votes held by the successful candidate as surplus, selected based on the next usable marked preference.

Other more recent methods transfer all votes held by successful candidate at a fraction of their value (the fraction derived by the surplus divided by the candidate's tally) and with reference to all the marked preferences on the ballots, not just the next usable preference. They may need the use of a computer.

The different methods may not produce the same result in all respects. But the front runners in the first count before any transfers are conducted are all or mostly elected in the end under any STV variant, so the various methods of transfers all produce much the same result.

Some variants of STV allow transfers to already elected or eliminated candidates, and these, too, can require a computer.<ref name="tidemanSTV">{{cite journal |last1=Tideman |first1=Nicolaus |author-link=Nicolaus Tideman |date=1995 |title=The Single Transferable Vote |journal=Journal of Economic Perspectives |volume=9 |issue=1 |pages=27–38 |doi=10.1257/jep.9.1.27 |doi-access=free}}</ref><ref>{{cite journal |last1=O’Neill |first1=Jeffrey C. |date=July 2006 |title=Comments on the STV Rules Proposed by British Columbia |url=http://www.votingmatters.org.uk/ISSUE22/INDEX.HTM |journal=Voting Matters |issue=22 |access-date=10 August 2013}}</ref>

In effect, the method produces groups of voters of much the same size so the overall effect is to reflect the diversity of the electorate, each substantial group electing one or more representatives that the group had voted for.

In Cambridge, under STV, 90 percent of voters see their vote help to elect a candidate, more than 65 percent of voters see their first choice candidate elected, and more than 95 percent of voters see one of their top three choices win.<ref>[http://www.nationalcivicleague.org/wp-content/uploads/2021/12/Model-City-Charter%E2%80%949th-Edition.pdf Model City Charter] National Civic League. 9th edition. 2021</ref>

Other reports claim that 90 percent of voters have a representative to whom they gave their first preference. Voters can choose candidates using any criteria they wish, the proportionality is implicit.<ref name="DMstvPdf" /> Another source states that, when STV was used between 1925 and 1955 in Cincinnati, 90 percent of voters saw their first choice elected or their vote used to elect a secondary preference, with about 60 to 74 percent of voters seeing their first choice elected, even if their vote was not used to elect that person because it was transferred on as a surplus vote.<ref>{{Cite book |last=Barber |title=Proportional Representation and Electoral Reform in Ohio |pages=191}}</ref>

Political parties are not necessary; all other prominent PR electoral systems presume that parties reflect voters wishes, which many believe gives power to parties.<ref name="tidemanSTV" /> STV satisfies the [[Comparison of electoral systems|electoral system criterion]] ''[[proportionality for solid coalitions]]''{{snd}} a solid coalition for a set of candidates is the group of voters that rank all those candidates above all others{{snd}} and is therefore considered a system of proportional representation.<ref name="tidemanSTV" />

However, the small district magnitude used in STV elections (usually 5 to 9 seats, but sometimes rising to 21) has been criticized as impairing proportionality, especially when more parties compete than there are seats available,<ref name="forder" />{{rp|50}} and STV has, for this reason, sometimes been labelled "quasi proportional".<ref name="AusOVC">{{cite book |first1=David M. |last1=Farrell |title=The Australian Electoral System: Origins, Variations, and Consequences |first2=Ian |last2=McAllister |date=2006 |publisher=[[UNSW Press]] |isbn=978-0868408583 |location=Sydney}}</ref>{{rp|83}}

While this may be true when considering districts in isolation, results {{em|overall}} are usually more proportional.

Even though Ireland has particularly small magnitudes (3 to 5 seats), results of STV elections are "highly proportional".<ref name="ideaEsd" />{{rp|73}}<ref name="ideaGallagher" /> In [[1997 Irish general election|1997]], the average magnitude was 4. Eight parties gained representation, four of them with less than 3% of first-preference votes nationally. Six independent candidates also won election.<ref name="laver" />

There have been claims made that STV handicaps certain extreme candidates because, to gain transfers based on back-up preferences and so improve their chance of election, candidates need to canvass voters beyond their own circle of supporters, and so need to moderate their views.<ref>{{Cite news |date=1 November 2011 |title=Referendum 2011: A look at the STV system |work=[[The New Zealand Herald]] |publisher=The New Zealand Herald |location=Auckland |url=http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10762976 |access-date=21 November 2014}}</ref> This argument is made from the high natural threshold STV provides with low district magnitude.<ref>{{cite magazine |date=30 April 2009 |title=Change the Way We Elect? Round Two of the Debate |url=https://thetyee.ca/Views/2009/04/30/STV2/ |magazine=The Tyee |location=Vancouver |access-date=21 November 2014}}</ref>

Conversely, widely respected candidates can win election even if they receive relatively few first preferences. They do this by benefiting from strong subordinate preference support. Of course, they must have enough initial support so that they are not in the bottom rung of popularity or they will be eliminated when the field of candidate is thinned.<ref name="DMstvPdf" />

[[Lewis Carroll|Charles Dodgson]] (Lewis Carroll), the polymath logician and author, developed a passionate interest<ref>{{citation |last=McLean |first=Iain |chapter=Voting |editor-first1=Robin |editor-last1=Wilson |editor-first2=Amirouche |editor-last2=Moktefi |title=The Mathematical World of Charles L. Dodgson (Lewis Carroll)  |publisher=Oxford |date=2019 |edition=Online Oxford Academic}}</ref> in voting methods. He believed RCV/STV to be fundamentally flawed, particularly regarding the allocation of "surplus" votes. His novel solution was to let the candidates themselves caucus and "club" votes together through the process of a negotiated consensus.<ref>{{cite web |title=Negotiated Consensus |url=https://gregblonder.medium.com/negotiated-consensus-bfde8bde5a20 |work=Medium |last=Blonder |first=Greg |date=21 October 2024 |access-date=5 May 2025}}</ref> As he stated:<ref>{{cite book |first=C. L. |last=Dodgson |author-link=Lewis Carroll |title=The Principles of Parliamentary Representation: Supplement |publisher=Oxford |date=1885 |p=7 |url=https://ia801308.us.archive.org/26/items/principlesofparl00carr/principlesofparl00carr_jpg.pdf}}</ref>

<blockquote>May I, in conclusion, point out that the method advocated in my pamphlet (where each elector names one candidate only, and the candidates themselves can, after the numbers are announced, club their votes, so as to bring in others besides those already announced as returned) would be at once perfectly simple and perfectly equitable in its result?</blockquote>

However, his entreaties to [[Robert Gascoyne-Cecil, 3rd Marquess of Salisbury|Lord Salisbury]], leader of the Conservative Party and future prime minister, to adopt "clubbing" were rejected in 1884<ref>{{cite book |last=Poundstone |first=William |title=Gaming the Vote: Why Elections Aren't Fair (and What We Can Do About It) |publisher=Hill and Wang |location=New York |date=2008 |isbn=9780809048922}}</ref> as "too sweeping a change". Subsequently, he joined with [[Thomas Hare (political reformer)|Thomas Hare]] and several Conservative and Liberal members of Parliament to found the Proportional Representation Society (later the [[Electoral Reform Society]]) and to pursue STV.